Kornblum, William
Harcourt Brace College Publishers, 1997
Buku Teks SO
Kornblum, William
Wadsworth and Cengage Learning, 2012
Buku Teks SO
Bryjak, George J
Allyn and Bacon, 1994
Buku Teks
Deller, Ruth A.
Emerald Publishing Limited, 2019
eBooks
Tepperman, Lorne
MGraw-Hill, 1991
Buku Teks SO